Coated articles are known in the art for use in window applications such as insulating glass (IG) window units, vehicle windows, monolithic windows, and/or the like.
Conventional low-E coatings are disclosed, for example and without limitation, in U.S. Pat. Nos. 6,576,349, 9,212,417, 9,297,197, 7,390,572, 7,153,579, and 9,403,345, the disclosures of which are hereby incorporated herein by reference.
Certain low-E coating utilize at least one transparent dielectric layer of titanium oxide (e.g., TiO2), which has a high refractive index (n), for antireflection and/or coloration purposes. See for example U.S. Pat. Nos. 9,212,417, 9,297,197, 7,390,572, 7,153,579, and 9,403,345. Although high refractive index dielectric material TiO2 is known and used in low-E coatings, TiO2 has a very low sputter-deposition rate and is not thermally stable upon heat treatment such as thermal tempering of about 650 C for 8 minutes, due to film crystallization (or change in crystallinity) in as-deposited or post-tempering state, which may in turn induce thermal or lattice stress on adjacent layers in the film stack. Such stress can further cause change in physical or material properties of the stack and hence impact on the Ag layer, which results in deteriorated low E stack performance. The low sputter deposition rate of TiO2 leads to significantly high costs associated with making low-E coatings including such layer(s).
Example embodiments of this invention solve these problems by providing a coated article including a low emissivity (low-E) coating having at least one infrared (IR) reflecting layer of a material such as silver, gold, or the like, and a plurality of high refractive index dielectric layers of or including a nitride of Zr and Al. In certain example embodiments, the high refractive index dielectric layers of or including a nitride of Zr and Al may be amorphous or substantially amorphous so as to allow the low-E coating to better withstand optional heat treatment (HT) such as thermal tempering. In certain example embodiments of this invention, the low-E coating includes a layer sequence of glass . . . ZrAlN/ZnO/Ag/contact/ZnO/ZrAlN . . . overcoat, where the ZnO inclusive layers may further contain Al or the like. It has been found that such a sequence advantageously provides for increased sputter deposition rates and thus lower cost, high transparency, good durability, good optical performance, and good thermal performance. In certain example embodiments, the low-E coating may be used in applications such as monolithic or insulating glass (IG) window unit, vehicle windows, of the like.
In an example embodiment of this invention, there is provided a coated article including a coating supported by a glass substrate, the coating comprising: a first high index dielectric layer comprising a nitride of Zr and Al on the glass substrate, wherein the first high index dielectric layer comprising the nitride of Zr and Al contains more Zr than Al; a first dielectric layer comprising zinc oxide on the glass substrate located over and directly contacting the first high index layer comprising the nitride of Zr and Al; a first infrared (IR) reflecting layer on the glass substrate, located over and directly contacting the first dielectric layer comprising zinc oxide; a first contact layer on the glass substrate located over and directly contacting the first IR reflecting layer; a second dielectric layer comprising zinc oxide on the glass substrate located over and directly contacting the first contact layer; a second high index dielectric layer comprising a nitride of Zr and Al on the glass substrate located over and directly contacting the second dielectric layer comprising zinc oxide, wherein the second high index dielectric layer comprising the nitride of Zr and Al contains more Zr than Al; and another dielectric layer on the glass substrate located over at least the first and second high index dielectric layers and the first IR reflecting layer.